This invention concerns the recovery and upgrading of carbonaceous material by in-situ hydrogenation. In one embodiment, the invention concerns the in-situ hydrogenation of an underground coal deposit, thus converting the coal into gaseous and liquid products that can be removed easily from the underground location and further processed above ground.
Under present technology, the economics for recovery and upgrading of gaseous and liquid hydrocarbons from underground deposits of lignite, coal, oil shale, tar sands, and heavy crudes are unattractive. Broadly, the current technology employed for producing saleable products from underground deposits of the above-mentioned carbonaceous materials involves at leat two of the following operations: (1) mining, (2) crushing and/or grinding, (3) washing or extraction, followed by flotation and phase separation, (4) retorting, and (5) upgrading or refining. Further, the current technology for recovery of heavy crudes is not commercially viable. While the examples set forth in the solution will be illustrated for coal or lignite, operations for other carbonaceous deposits such as tar sands, heavy crudes, and oil shale are applicable.
The prior art teaches some of the aspects of the present invention. For example, U.S. Pat. Nos. 3,084,919 (Slater); 3,208,514 (Dew and Martin); and 3,327,782 (Hujsak) teach methods of recovering hydrocarbons by the use of hydrogen. Typically, these processes involve the use of in-situ combustion in a formation, to heat the formation and to reduce the viscosity of the hydrocarbon values in the unburned portions, followed by the introduction of a hydrogen stream, for hydrogenation of these hydrocarbon values. The hydrotreated products are then recovered and processed.
U.S. Pat. No. 3,598,182 (Justheim) introduces hot hydrogen into an underground formation, to heat the formation, to promote cracks and fissures in the formation, to reduce the viscosity of any available hydrocarbon values, and to hydrocrack at least a portion of these values. Products are then recovered and processed.
A majority of the above processes involve combustion of at least a portion of the formation. And Justheim uses an extensive temperature regulating system.